Autologous cell sources in therapeutic vasculogenesis: In vitro and in vivo comparison of endothelial colony–forming cells from peripheral blood and endothelial cells isolated from adipose tissue

Background aims. Autologous endothelial cells are promising alternative angiogenic cell sources in trials of therapeutic vasculogenesis, in the treatment of vascular diseases and in the field of tissue engineering. A population of endothelial cells (ECs) with long-term proliferative capability, endothelial colony–forming cells (ECFCs), can be isolated from human peripheral blood. ECFCs are considered an endothelial precursor population. They can be expanded in cell factories in sufficient numbers for clinical applications, but because the number of isolated primary ECs is low, the culture period required may be long. Another EC population that is easily available in the autologous setting and may be expanded in vitro through several population doublings are ECs from adipose tissue (AT-ECs). Methods. Through extensive comparisons using whole-genome microarray analysis, morphology, phenotype and functional assays, we wanted to evaluate the potential of these EC populations for use in clinical neovascularization. Results. Global gene expression profiling of ECFCs, AT-ECs and the classical EC population, human umbilical vein ECs, showed that the EC populations clustered as unique populations, but very close to each other. By cell surface phenotype and vasculogenic potential in vitro and in vivo, we also found the ECFCs to be extremely similar to AT-ECs. Conclusions. These properties, together with easy access in the autologous setting, suggest that both AT-ECs and ECFCs may be useful in trials of therapeutic neovascularization. However, AT-ECs may be a more practical alternative for obtaining large quantities of autologous ECs.